A dentist may decide to extract the tooth to prevent recurrent trouble.牙医可能会决定拔掉那颗牙，以免反复发作。When not removed, plaque causes tooth decay and gum disease.牙斑如果不清除就会导致牙齿蛀蚀和牙龈疾病。He fought tooth and nail to keep his job.他竭尽全力保住...
the coefficient of friction摩擦系数A coefficient of one means the markets move perfectly in step.系数为1表示各个市场的步调完全一致。The distribution coefficient equation is still valid for any value of n.对任一级n,分配系数关系式仍然是成立的....